The long-term industrial and societal impact of semiconductor nanofabrication technology depends on its production rate, reliability, robustness, yield, cost, and the integration capability with micro- and macroscale systems. In recent years, various nanofabrication technologies have been developed for creating one-dimensional nanostructures, such as nanowhiskers, nanorods and nanowires, on semiconductor substrates. These and other nanostructures have attracted significant attention in the past decade owing to their numerous applications in electronics, photonics, energy conversion and storage, and in interfacing with biomolecules and living cells.
Historically, semiconductor nanostructures have been created by either bottom-up or top-down processes. Bottom-up processes generally refer to growth techniques based on various phase transition mechanisms, such as vapor-solid (VS), vapor-liquid-solid (VLS), and solid-liquid-solid (SLS). Top-down processes typically rely on nanoscale patterning with various nanolithography techniques, such as photo-, electron beam, nanosphere, nanoimprint, soft, and block copolymer lithography, followed by one or more etching steps. Since these approaches involve nanoscale pre-patterning, surface-area-sensitive assembly processes, or extreme fabrication conditions, they are often limited by high costs and low yields as well as by the consequent industry incompatibility.
The inventors have recognized that an improved process for the fabrication of semiconductor nanostructures that has an ultrahigh throughput, good reliability and a high yield at a relatively low cost would have immediate scientific and industrial applications.